Barriers, facilitators, and other factors associated with health behaviors in childhood, adolescent, and young adult cancer survivors: A systematic review

Abstract Background Healthy behaviors are paramount in preventing long‐term adverse health outcomes in childhood, adolescent, and young adult (CAYA) cancer survivors. We systematically reviewed and synthesized existing literature on barriers, facilitators, and other factors associated with health behaviors in this population. Methods MEDLINE and PsycInfo were searched for qualitative and quantitative studies including survivors aged 16–50 years at study, a cancer diagnosis ≤25 years and ≥2 years post diagnosis. Health behaviors included physical activity, smoking, diet, alcohol consumption, sun exposure, and a combination of these behaviors (defined as health behaviors in general). Results Barriers, facilitators, and other factors reported in ≥2 two studies were considered relevant. Out of 4529 studies, 27 were included (n = 31,905 participants). Physical activity was the most frequently examined behavior (n = 12 studies), followed by smoking (n = 7), diet (n = 7), alcohol (n = 4), sun exposure (n = 4), and health behavior in general (n = 4). Relevant barriers to physical activity were fatigue, lack of motivation, time constraints, and current smoking. Relevant facilitators were perceived health benefits and motivation. Influence of the social environment and poor mental health were associated with more smoking, while increased energy was associated with less smoking. No relevant barriers and facilitators were identified for diet, alcohol consumption, and sun exposure. Barriers to healthy behavior in general were unmet information needs and time constraints whereas lifestyle advice, information, and discussions with a healthcare professional facilitated healthy behavior in general. Concerning other factors, women were more likely to be physically inactive, but less likely to drink alcohol and more likely to comply with sun protection recommendations than men. Higher education was associated with more physical activity, and lower education with more smoking. Conclusion This knowledge can be used as a starting point to develop health behavior interventions, inform lifestyle coaches, and increase awareness among healthcare providers regarding which survivors are most at risk of unhealthy behaviors.


| INTRODUCTION
The number of childhood, adolescent, and young adult (CAYA) cancer survivors is increasing due to survival rates of up to approximately 80% in high-income countries. 1,2][5][6][7][8] These health outcomes can lead to hospitalization, disability, reduced quality of life, and premature mortality. 98][19][20][21] Consequently, the adoption and maintenance of healthy behaviors has become paramount in the prevention of long-term adverse health outcomes in CAYA cancer survivors.
However, CAYA cancer survivors may face specific barriers and facilitators when trying to adopt healthy behaviors.For example, physical limitations resulting from cancer treatment, chronic pain, and fatigue may hinder engagement in physical activity. 22,23On the contrary, survivors might be more aware of their elevated health risks, which may increase their motivation to change their behavior. 24Positive or negative attitudes and beliefs also play an important role in shaping survivors' willingness to adopt healthy behaviors. 25,26n order to develop targeted interventions tailored to the individual needs and preferences of CAYA cancer survivors, more knowledge is needed about the barriers, facilitators, and other factors associated with their health behaviors.In addition, a comprehensive understanding of the barriers, and facilitators that influence the different health behaviors of CAYA cancer survivors can inform guidelines and help healthcare providers (HCPs) involved in survivorship care to promote healthy habits.Knowledge about other factors, such as sociodemographic, treatmentand clinical factors, can be used to raise awareness among CAYA cancer survivors at high risk of unhealthy lifestyle behaviors.Therefore, this systematic review aimed to synthesize the existing evidence on the relevant barriers, facilitators, and other factors associated with health behaviors in CAYA cancer survivors.

| Study designs
All study designs were eligible for inclusion except narrative and systematic reviews and case reports.We only included quantitative studies that reported multivariable and health behavior in general (n = 4).Relevant barriers to physical activity were fatigue, lack of motivation, time constraints, and current smoking.Relevant facilitators were perceived health benefits and motivation.Influence of the social environment and poor mental health were associated with more smoking, while increased energy was associated with less smoking.No relevant barriers and facilitators were identified for diet, alcohol consumption, and sun exposure.Barriers to healthy behavior in general were unmet information needs and time constraints whereas lifestyle advice, information, and discussions with a healthcare professional facilitated healthy behavior in general.Concerning other factors, women were more likely to be physically inactive, but less likely to drink alcohol and more likely to comply with sun protection recommendations than men.Higher education was associated with more physical activity, and lower education with more smoking.

Conclusion:
This knowledge can be used as a starting point to develop health behavior interventions, inform lifestyle coaches, and increase awareness among healthcare providers regarding which survivors are most at risk of unhealthy behaviors.

K E Y W O R D S
barriers, CAYA cancer survivors, facilitators, factors, health behaviors, healthy lifestyle, pediatric oncology, systematic review | 3 of 30 de BEIJER et al. models, as these provide more robust analyses and better control for confounding variables, increasing the reliability of the results.In addition, only English-language studies published after 2000 were included, as earlier research largely overlooked the impact of health behavior on late adverse health outcomes.

| Participants
To ensure inclusivity without compromising reliability and to account for differences in international definitions of age thresholds for childhood cancer, studies were eligible if ≥75% of the study population was diagnosed with cancer <25 years of age, ≥50% of the population was ≥2 years after their primary cancer diagnosis, and participants were aged 16-50 years at the time of study.Studies including participants still undergoing cancer treatment were excluded.Studies with mixed samples (e.g., survivors aged < and ≥25 years at diagnosis) were included if results allowed separation.

| Outcomes
Outcomes were barriers, facilitators, and other factors associated with physical activity, smoking, diet, alcohol consumption, sun exposure, and a combination of health behaviors (health behavior in general).Barriers were interpreted as influencing the persistence of unhealthy behaviors or hindering/limiting healthy behaviors, whereas facilitators were interpreted as factors supporting engagement in healthier behaviors.In addition, barriers and facilitators were interpreted as potentially modifiable, for example, through lifestyle interventions.Other variables that were associated with health behavior and behavior change but were considered nonmodifiable or very difficult to modify were categorized separately as other factors, that is, sociodemographic and clinical characteristics.Factors that influence the persistence of unhealthy behaviors or hinder/limit healthy behaviors were termed "risk factors", while factors that support engagement in healthier behaviors were termed "supportive factors".
We distinguished between outcomes derived from qualitative and/or (semi-)quantitative survey studies and those derived from quantitative studies, including observational or (semi)experimental studies with measures of association as outcomes.All suboutcomes, such as-in the case of smoking-smoking cessation, smoking rate, and quit attempts, were aggregated to the primary health behavior of interest, that is, smoking.

| Search strategy for identification of studies
We conducted a systematic literature search in MEDLINE (Ovid until 15 April 2021 and PubMed from 15 April 2021 to 26 April 2023 for the updated search) and PsycInfo until 15 April 2021 (Appendix B).Reference lists of included studies and reviews were searched for studies not included in the electronic database searches.All authors were asked to identify any missing studies that had not been identified in the previous searches.

| Study selection
After removing duplicates, two independent reviewers assessed the titles and abstracts using Rayyan (https:// rayyan.ai).Studies meeting the inclusion criteria were retrieved for full-text review.The reviewers discussed discrepancies that arose at either stage.Third party arbitration was not required.Two studies by Emmons   2005) described the outcomes of the intervention. 20,27As both studies met the inclusion criteria, we included them in our review.

| Data extraction
Standardized evidence tables (Appendix S1) were created to ensure the accuracy and consistency of data collection.These evidence tables included information on study design, participant characteristics, and outcomes.The tables were prepared by one author and checked by another author.In case of discrepancies or disagreements, the authors agreed by discussion.

| Data synthesis
We have summarized the results in two separate tables: one for barriers and facilitators from qualitative and (semi-)quantitative studies (Table 1) and one for significant barriers, facilitators, and other factors from quantitative studies (Table 2).These tables contain information about the study design, the participants and a summary of findings.Additionally, we created two overview tables (Tables 3 and 4) for all the barriers, facilitators, and other factors extracted from Tables 1 and 2. We categorized the barriers, facilitators, and other factors outlined in Tables 3 and 4 based on their content to enhance clarity
3.1.2| Smoking (n = 7 studies, n = 5420 participants) Seven barriers, six facilitators, five risk factors, and 12 supportive factors were associated with smoking in the included studies.Barriers reported in at least two studies were negative influence of the social environment (n = 2, e.g., smoking in the household or a higher proportion of smokers in the social network 27,44 ) and poor mental health (n = 2 27,42 ).On the contrary, increased energy (n = 2 20,26 ) was identified as a facilitator in at least two studies..1.3| Diet (n = 7 studies, n = 3695 participants) Six barriers (e.g., not liking the taste of certain foods), seven facilitators (e.g., peer support), two risk factors (e.g., Hispanic or Black ethnicity), and 10 supportive factors (e.g., female sex) were associated with diet in one of the included studies.No barriers, facilitators, or factors were reported in at least two studies.Abbreviations: ALL, acute lymphocytic leukemia, BMI, body mass index, CAYA, childhood, adolescent, and young adult, CCS, childhood cancer survivors, CI, confidence interval, CNS, central nervous system, CRT, cranial radiotherapy, Gy, gray, RR, risk ratio, OR, odds ratio.
Note: This table displays only the significant study results; non-significant results and descriptions of the models used for each included study are shown in the evidence tables (Supplementary File A).Barriers contribute to the persistence of unhealthy behaviors, while facilitators support the transition to healthier choies.
T A B L E 2 (Continued) | 13 of 30 de BEIJER et al.
T A B L E 3 Barriers and facilitators to health behaviors.

Barriers Facilitators Barriers Facilitators Barriers Facilitators Barriers Facilitators Barriers Facilitators Barriers Facilitators
Information, knowledge, and skills Lifestyle advice and information Health promotion conversation with healthcare professional N = 2 [28,30]   Being able to contact healthcare professional for lifestyle choices Unmet information needs Lack of knowledge and skills N = 2 [26,32]   Knowledge and skills Learning how to deal with physical limitations Counseling Self-management and cognitive processes Self-help Lack of self-efficacy Self-efficacy Lack of confidence Lack of motivation [25,26,31,34]   (Self)-motivation [31,35]   Positive reinforcement Conscious decision-making (Continues)

Positive family influence
| 15 of 30 de BEIJER et al.

Barriers Facilitators Barriers Facilitators Barriers Facilitators Barriers Facilitators Barriers Facilitators Barriers Facilitators
Negative family influence Positive social environment Negative influence of social environment Peer support Positive influence of social media Negative influence of social media Stimulating work environment Sedentary profession Obligatory classes at school Doctors limiting physical activities

Barriers Facilitators Barriers Facilitators Barriers Facilitators Barriers Facilitators Barriers Facilitators Barriers Facilitators
Available professional support Walkability of the neighborhood Proximity of facilities Having adaptive equipment Digital prints/ materials Mental health and quality of life Good mental health Poor mental health Anxiety Suicidal behavior Increased energy N = 2 [20,26]   Poor physical quality of life Poor mental quality of life Perceived vulnerability Fear regarding future health

Behavioral regulation
Too much screen time | 17 of 30 de BEIJER et al.
least two studies.However, in terms of factors, men had significantly higher levels of alcohol consumption than women, especially with regard to binge drinking (n = 2 43,48 ).
3.1.5| Sun exposure (n = 4 studies, n = 754 participants) The included studies reported zero barriers, two facilitators, four risk factors, and three supportive factors associated with (increased) sun exposure.No barriers or facilitators were reported in at least two studies.However, women were significantly more likely than men to adhere to sun exposure recommendations (n = 3 34,46,49 ).
3.1.6| Health behavior in general (n = 4 studies, n = 403 participants) Twelve barriers and 19 facilitators associated with health behavior in general were identified in the included studies.
Barriers identified in at least two studies were unmet information needs (n = 2 29,30 ) and time constraints (n = 2 29,30 ).Lifestyle advice and information (n = 3 [28][29][30] ) and having a health promotion conversation with a healthcare professional (n = 2 28,30 ) were identified as facilitators in at least two studies.There were no other factors associated with health behavior in general.

| DISCUSSION
To our knowledge, this systematic review is the first to provide a comprehensive overview of the evidence on barriers,

Barriers Facilitators Barriers Facilitators Barriers Facilitators Barriers Facilitators Barriers Facilitators Barriers Facilitators
Currently smoking N = 3 [38,39,47]   Not currently smoking Being a past smoker Drinking initiation at a young age Higher (baseline) exercise frequency Not liking the taste of certain foods Note: Numbers in brackets refer to the reference number of an included study.Barriers (red colors) contribute to the persistence of unhealthy behaviors, while facilitators (green colors) support (the transition to) healthier behaviors.The darkness of the color corresponds to the frequency of the barriers or facilitators on a 3-point scale, with darker colors representing higher frequencies.

T A B L E 3 (Continued)
T A B L E 4 Sociodemographic, cancer and treatment related and other factors associated with health behavior.Female sex [34,49]   Older age

Smoking
Younger age Being married or living with a partner Having children N = 2 [31,39]   Lower level of education Higher level of education Lower level of parent's education Unknown parent's education Non-Hispanic White ethnicity Hispanic, Black or Other Non-Hispanic ethnicity N = 2 [38,47]   Hispanic or Black ethnicity Lower income Being unable to work Being a student Cancer-and treatment-related factors Being a survivor of lymphoma Being a survivor of CNS tumor Diagnosis including hematological malignancies

Smoking
Other cancer diagnosis than leukemia Cancer diagnosis at a younger age Cancer diagnosis during late adolescence Higher cancer treatment intensity Surgery only Having had surgery Radiotherapy N = 2 [38,50]   Cranial radiotherapy No cranial radiotherapy Chemotherapy and/or cranial radiotherapy Thoracic radiotherapy Bone marrow transplantation (vs.chemotherapy) Lower abdomen radiation dose 4600-8999 Mg/m2 cumulative glucocorticoid dose Intrathecal methotrexate or cranial radiation Familiarity of primary care physician with cancer-related problems facilitators, and other factors associated with health behaviors in CAYA cancer survivors.Physical activity was the most commonly studied health behavior in this systematic review.The most frequently identified barriers to physical activity were fatigue, time constraints, lack of motivation, current smoking, lack of knowledge and skills, fear of injury, financial constraints, being either underweight, or obese, and experiencing physical limitations.Of note, feeling fatigued may reduce physical activity, but regular physical activity may in its turn reduce cancer-related fatigue. 51,53Female sex was the most commonly identified risk factor associated with lower levels of physical activity, followed by a treatment history including radiotherapy, having children, having less education, and being of Hispanic, black, or other non-Hispanic ethnicity.Facilitators for physical activity included perceived health benefits and levels of motivation.Higher education was the only supportive factor associated with increased physical activity in at least two studies.
5][56][57] Besides, Brown and colleagues recently synthesized evidence from eight qualitative studies of barriers and facilitators to physical activity from the perspective of childhood cancer survivors. 58Parental influence and support were found to be major themes, possibly because parental factors were the main focus of two of the included studies.The current review adds to these findings by synthesizing evidence from both qualitative and quantitative studies, including the impact of sociodemographic, cancer and treatment-related factors on survivors' physical activity levels.
Higher smoking rates among CAYA cancer survivors were related to lower levels of education, poor mental health, and having more peers or household members who smoke.In contrast, increased energy was associated with lower smoking rates.Men were more likely than women to have higher levels of alcohol consumption.These findings are consistent with the literature on smoking and alcohol consumption in the general population [59][60][61] and highlight the importance of sociodemographic factors such as sex and educational level in identifying those at risk of unhealthy behaviors.Furthermore, as smoking and mental health are linked through the withdrawal effect of tobacco, HCPs can explain to smokers that the decrease in nicotine levels after smoking a cigarette leads to withdrawal symptoms such as poor concentration, insomnia, feelings of tension, restlessness, low mood, and anxiety. 60ne strategy that can be used to support smoking cessation is cognitive behavioral therapy (CBT), which helps people understand the relationships between their thoughts, Having had a second cancer Longer time since treatment completion Other factors Amputation of lower limb Fair/easily burned skin type N = 1 [51]   Note: Numbers in brackets refer to the reference number of an included study.Green colors indicate a positive association with the health behavior.Red colors indicate a negative association.The darkness of the color corresponds to the frequency of the factors on a 3-point scale, with darker colors representing higher frequencies.TABLE 4 (Continued)  feelings, behaviors, and physical experiences. 60CBT can also be used for improving other health behaviors.This review also found that women were more likely than men to adhere to sun exposure recommendations, with the exception of occasional sun exposure.This is consistent with research in the general population suggesting that men are more likely to perceive the inconvenience and cost of sunscreen sun-protective clothing as barriers to their sun-protective behavior. 62In addition, men tend to perceive skin damage from sun exposure as less severe than women do. 62e did not find any barriers, facilitators, or other factors associated with a healthy diet that were identified by two or more studies.In the general population, systematic reviews found that social environment plays an important role in dietary health behavior, along with automaticity, self-regulation, motivational regulation, subjective norm, and relationships with sedentary behavior. 63,64However, the evidence is suggestive at best, because of the widespread use of cross-sectional designs in the studies included in the reviews.More research is therefore needed to understand the barriers and facilitators associated with a healthy diet among both the general population and, particularly, CAYA cancer survivors.

| Health behavior interventions and identification of survivors most at risk
The barriers and facilitators identified in this review can be used as a starting point for developing health behavior interventions that meet the needs and preferences of individual CAYA cancer survivors and support them in adopting healthier lifestyles.For example, a targeted health behavior intervention can help survivors to manage their clinical symptoms of fatigue and time constraints, and increase their motivation by addressing their individual preferences and needs and by emphasizing the benefits of healthy lifestyles.A recent systematic review and meta-analysis on healthy lifestyle interventions found that current health behavior interventions are primarily exercise-based without significant effects on physical outcomes such as physical fitness, fatigue, and body mass index. 65Therefore, a different, more holistic and individualized approach to health behavior interventions is warranted. 66Overall, further clinical trials are needed to increase the body of research on effective health behavior interventions for CAYA cancer survivors.Such interventions should build on the accumulated evidence on barriers and facilitators and address strategies to overcome fatigue, increase and sustain motivation over time, and include aspects of time management techniques.Moreover, engaging key stakeholders such as survivors, HCPs, and policymakers at the initial stages of intervention development increases the likelihood of creating interventions that are not only delivered on time and within budget but also deemed acceptable and feasible. 67he insights in relevant risk and supportive factors associated with health behaviors can help to increase awareness among HCPs regarding which survivors are most at risk of certain unhealthy behaviors.urvivorship care clinics should prioritize the integration of health behavior support services such as lifestyle coaching and ensure that HCPs are adequately equipped with the necessary knowledge and skills to support survivors in adopting and maintaining healthy behaviors.In addition, a systematic review of 17 randomized controlled trials among all types of patients showed that using deliberate communication strategies when providing information can improve patient outcomes more effectively than not using such strategies. 69Therefore, when HCPs aim to encourage survivors to engage in specific health behaviors, they may particularly benefit from using explicit persuasive information strategies.

| Strengths and limitations
The methodology used in this review had several strengths.First, we followed a rigorous and transparent approach, including a comprehensive search strategy and the involvement of two independent reviewers in the screening of studies and data extraction.We included both quantitative and qualitative studies to enrich the scope and depth of our review.
et al. partially overlapped: Emmons et al. (2003) described the baseline data collection and intervention design of the Partnership for Health Study, and Emmons et al. (

Note: 2
Barriers contribute to the persistence of unhealthy behaviors, while facilitators support the transition to healthier choices.Quantitative studies examining significant barriers, facilitators, and other factors associated with health behaviors.

Study (design) and participants (N) Barriers and facilitators
Qualitative and semi-quantitative survey studies examining barriers and facilitators to health behaviors.
T A B L E 1
• Being of fair/easily burned skin type (p = 0.02) • Perceiving greater relative susceptibility to skin cancer compared with non-cancer survivors (p = 0.02) T A B L E 2 (Continued) (Continues)

Study (design) and participants (N) Barriers, facilitators, and other factors significantly associated with health behaviors
Three barriers, one facilitator, seven risk factors, and four supportive factors associated with (reducing) alcohol consumption were reported in the included studies.No barriers or facilitators were reported in at factors related to cancer history and treatment, such as age at diagnosis, cancer diagnosis, and cancer treatment, highlights the possibility that these specific factors may not be of substantial importance in relation to health behaviors in CAYA cancer survivors.In other words, this review indicates that the primary results identified are not inherently specific to CAYA survivors.Consequently, HCPs and lifestyle coaches may need to broaden their focus beyond medical history when assisting CAYA cancer survivors to improve their health behaviors and adopt new habits.For instance, other individual characteristics such as sex and educational attainment should be taken into account.

4.2 | The importance of knowledge dissemination
This review highlights the importance of increasing knowledge about healthy behaviors in general among CAYA cancer survivors through health behavior advice, information dissemination, and health promotion discussions with HCPs.These findings align with a recent qualitative study of HCPs, which highlighted the critical role of education and training of HCPs in effectively guiding CAYA cancer survivors toward healthy behaviors.

25 or/21-24 = survivors late effects
Our comprehensive review examined different aspects of health behavior, including physical activity, smoking, diet, alcohol consumption, sun exposure, and health behavior in general.Barriers, such as fatigue, unmet information needs, time constraints, lack of motivation, social influences, poor mental health, and facilitators, such as the need for lifestyle advice and health promotion discussions with HCPs, highlight the importance of targeted interventions.The identification of other factors associated with health behavior outcomes, including (among others) sex and educational attainment, highlights the need to consider individual context and sociodemographic characteristics.Overall, our findings can be used as a starting point for the development of more targeted and effective health behavior change interventions to promote healthy behaviors in CAYA cancer survivors, to support them in adapting these behaviors, and to inform lifestyle coaches.Knowledge of other factors can be used to raise awareness among HCPs of which survivors are most at risk of unhealthy behaviors.We would like to thank Rikie Deurenberg, who developed the search strategies FOR OVID-MedLine and PsycInfo, and all the PanCareFollowUp partner institutes and coauthors who have been involved in this study.The PanCareFollowUp Consortium, established in 2018, is a unique and multidisciplinary collaboration between 14 project partners from 10 European countries, including patient experts (https:// panca refol lowup.eu).The aim of the consortium is to improve the quality of life for survivors of childhood, adolescent, and young adult (CAYA) cancer by bringing evidence-based, personcentered care to clinical practice.The PanCareFollowUp Consortium has developed and evaluated two interventions, including a person-centered and guideline-based model of survivorship care (Care Intervention) and an eHealth lifestyle coaching model (Lifestyle intervention).After the project, Replication Manuals that contain the instructions and tools required for implementation of the PanCareFollowUp interventions will be freely distributed.FUNDING INFORMATIONThis work was supported by the European Union's Horizon 2020 Framework Program (Grant Number 824982).The funder had no role in study design, data col-lection, data analysis, data interpretation, or in writing the report.The material presented and views expressed here are the responsibility of the author(s) only.The EU Commission takes no responsibility for any use made of the information set out. (aml or anll or lymphoma or lymphom* or hodgkin* or T-cell or B-cell or non-hodgkin or sarcoma or sarcom* or Ewing* or osteosarcom* or wilms* or nephroblastom* or neuroblastom* or rhabdomyosarcom* or teratom* or hepatom* or hepatoblastom* or PNET or medulloblastom* or PNET* or (neuroectodermal adj2 tumors adj2 primitive) or retinoblastoma or retinoblastom* or meningiom* or gliom*).tw,id.adj tumo?r*) or (brain adj neoplasm?)or (central adj nervous adj system adj neoplasm?)or (central adj nervous adj system adj tumo?r?) or (central adj nervous adj system adj cancer?) or (brain adj cancer*) or (brain adj neoplasm*) or (intracranial adj neoplasm*) or (leukemia adj lymphocytic adj acute*)).tw,id.cessat*) or nutrition or diet* or self-care or (dietary adj3 chang*) or (weight adj3 control*) or (stimulat* adj3 physical)).tw,id.38 ((body adj2 weight adj3 maintena*) or exercis* or walking or training or smoking or (physical adj3 exercis*) or diet or alcohol or eating).tw,id.(internet adj3 (support or self*)).tw,id.
However, this review brings together very different study designs and methodologies such as studies reporting on survivors' perceived influences on behavior and cohort studies reporting on risk factors.The results should therefore be interpreted funding acquisition (supporting); methodology (equal); writing -review and editing (equal).Vera Araújo-Soares: Conceptualization (equal); funding acquisition (supporting); methodology (equal); writing -review and editing (equal).Magdalena Balcerek: Methodology (equal); writing -review and editing (equal).Edit Bardi: Methodology ACKNOWLEDGMENTS